SN3 SHORT NOTE 5M

Write a short note on acute rheumatic fever — pathogenesis, Jones criteria and management.

General Medicine · Final Professional

Definition & Epidemiology

Acute rheumatic fever (ARF) is a delayed, immunologically mediated, multisystem inflammatory sequel to group A beta-haemolytic streptococcal (GAS) pharyngitis, affecting the heart, joints, brain, skin and subcutaneous tissue. It occurs typically in children aged 5–15 years, 2–4 weeks after an untreated throat infection. India carries one of the world's largest burdens of ARF and rheumatic heart disease, driven by overcrowding, poverty and limited access to treatment of sore throat.

Only pharyngeal infection causes ARF — streptococcal skin infection does not.

Pathogenesis

Molecular mimicry: antibodies and T cells raised against the streptococcal M protein and N-acetylglucosamine cross-react with structurally similar host antigens — cardiac myosin and valve endothelium (laminin), synovium, and neuronal tissue in the basal ganglia. The result is a sterile inflammatory response at these sites. The characteristic myocardial lesion is the Aschoff nodule, a perivascular granuloma with Anitschkow cells. Genetic susceptibility (HLA class II alleles) determines who responds this way.

Clinical Features — Revised Jones Criteria (2015)

Diagnosis requires evidence of preceding streptococcal infection plus two major criteria, or one major and two minor criteria. The 2015 revision distinguishes low-risk from moderate/high-risk populations (which includes India), with lower thresholds in the latter.

Major criteria	Notes
Carditis	Pancarditis — endocarditis, myocarditis, pericarditis. The 2015 revision accepts subclinical carditis on echocardiography as a major criterion. Mitral valve most often affected, then aortic. The only manifestation causing permanent damage
Arthritis	Migratory polyarthritis of large joints — knees, ankles, elbows, wrists; exquisitely painful, dramatically responsive to salicylates; never deforming. In high-risk populations monoarthritis and polyarthralgia also count
Chorea (Sydenham's)	Late manifestation (up to 6 months); purposeless involuntary movements, emotional lability, "milkmaid's grip"; may occur alone and is diagnostic by itself
Erythema marginatum	Evanescent, non-pruritic, pink macules with serpiginous spreading margins on the trunk; rare and easily missed in dark skin
Subcutaneous nodules	Painless, firm, mobile nodules over extensor surfaces and bony prominences; rare, and associated with severe carditis

Minor criteria: fever, arthralgia (if arthritis is not a major criterion), raised ESR or CRP, and prolonged PR interval on ECG (if carditis is not a major criterion).

Evidence of preceding streptococcal infection: raised or rising ASO titre or anti-DNase B, positive throat culture, or positive rapid antigen test.

CLINICAL PEARL

"Arthritis licks the joints but bites the heart." The arthritis of ARF is dramatic, migratory and completely resolves without deformity, whereas the carditis may be clinically silent yet leaves permanent valve damage. This is exactly why the 2015 criteria added echocardiography for subclinical carditis — and why every suspected case must have an echocardiogram.

Investigations

Throat swab culture and rapid antigen test; ASO titre (rising titres are more useful than a single value); ESR and CRP; CBC; ECG for PR prolongation and conduction disturbance; echocardiography in every case to detect valvulitis and subclinical carditis; chest X-ray for cardiomegaly and failure.

Management

1. Eradicate the streptococcus — benzathine penicillin G by a single intramuscular injection, or oral penicillin V for 10 days; a macrolide in penicillin allergy. This is given regardless of throat culture result.

2. Anti-inflammatory therapy

Arthritis without carditis: aspirin or NSAIDs — response is rapid and dramatic; failure to respond within 48 hours should make you question the diagnosis.
Moderate to severe carditis: corticosteroids (prednisolone), tapered over weeks, with aspirin overlap on withdrawal to prevent rebound.

3. Supportive — bed rest during active carditis, treatment of heart failure (diuretics, ACE inhibitors), and management of chorea with rest, a quiet environment, and where necessary carbamazepine or valproate.

4. Secondary prophylaxis — the most important long-term measure

Continuous antibiotic prophylaxis prevents recurrent attacks, each of which worsens valve damage. Intramuscular benzathine penicillin every 3–4 weeks is the standard, with oral penicillin as an alternative for those refusing injections.

Category	Duration of Prophylaxis
ARF without carditis	5 years, or until age 21 — whichever is longer
ARF with carditis, no residual valve disease	10 years, or until age 21 — whichever is longer
ARF with carditis and residual valve disease	10 years, or until age 40 — sometimes lifelong

5. Prevention — primary prevention by prompt diagnosis and antibiotic treatment of streptococcal sore throat, together with improved living conditions, remains the only way to reduce the national burden.

NEEDS VERIFICATION

Benzathine penicillin doses by body weight, aspirin and prednisolone regimens, and prophylaxis durations — confirm against current WHO/Indian cardiology guidance.

All questions in Immunology & Rheumatology

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